Tomase: Steelers imploding like 2 other franchises that thought they could challenge Patriots

The news that the 0-1-1 Steelers will now entertain offers for disgruntled running back Le'Veon Bell adds another team to the list of contenders that have been outlasted by the Patriots.

Starting with the Rams in 2001 and continuing through the Peyton Manning Colts -- not to mention the Peyton Manning Broncos -- and the Joe Flacco Ravens, the Patriots have consistently watched rivals come and go.

The Steelers, however, belong in a separate class of challengers that imploded before their expected expiration date. After all, Ben Roethlisberger, Antonio Brown, and Bell represent the most dangerous QB-WR-RB triumvirate in the league.

But with Brown sniping at former team employees on Twitter and Bell a holdout over his refusal to sign the franchise tender, the Steelers appear on the verge of collapse. In that sense, they look poised to join two other clubs that had the makings of a dynasty worthy of the Patriots, but ultimately couldn't stand the test of time.

The first and most obvious are Pete Carroll's Legion of Boom Seahawks. They destroyed the Broncos in a throwback NFC Super Bowl thrashing in 2013, winning SB XLVIII by a 43-8 blowout. They returned a year later and were only a few feet away from repeating when Malcolm Butler jumped a route and made history.

The Patriots winning that game started Seattle on a downward spiral of in-fighting and recriminations, as well as a steady decline in play. Since 2013, Seattle's win totals have dropped from 13 to 12 to 10 to 10 to nine to this year's 0-2 start.

Along the way, Seattle has deconstructed one of the NFL's best defenses, scattering standouts like Michael Bennett, Richard Sherman, and Bruce Irvin to the wind, losing hard-hitting safety Kam Chancellor to a serious neck injury that necessitated his retirement, and watching the last man standing, safety Earl Thomas, hold out until the eve of this season before reluctantly rejoining the team.

The Seahawks are officially the Dynasty that Wasn't, and Sports Illustrated delved into the petty animosities that split them, with many veteran defenders believing quarterback Russell Wilson received kid-gloves treatment from Carroll and others wondering how the whole thing had crumbled.

Meanwhile, the Patriots have trucked right along, winning another Super Bowl with a miracle comeback over Atlanta and losing a shootout last year to the Eagles despite more than 500 yards passing from Tom Brady.

The other team on this list may sound counterintuitive, given its success against the Pats in the only game that matters, but after winning two Super Bowls and two division titles from 2007-11, the Giants had the makings of a group with staying power.

Instead, they slowly unraveled. They've reached 10 wins just once in the last six seasons, losing the wild card game in a blowout at Green Bay in their only playoff appearance since beating the Patriots in Super Bowl XLVI.

Quarterback Eli Manning had just turned 31 when he beat Brady in the Super Bowl for the second time. There was no reason to think New York couldn't continue to contend for titles, especially when outrageous talents like Odell Beckham Jr. joined the team.

But the Giants have finished below .500 in four of the last five seasons, and they're off to an 0-2 start this year. The days of building a fearsome pass rush around Michael Strahan, Justin Tuck, Osi Umenyiora, and/or Jason Pierre-Paul are long gone.

In their place is a middle-of-the-road team that embarrassed Manning with a late-season benching to end a record starting streak, and then came crawling back to him as a starter this year, anyway. More than ever, the Giants' two Super Bowl wins feel not so much like flukes, but certainly outliers.

Meanwhile, the Patriots just keep doing what they're doing, even amidst reports of tension between Brady and head coach Bill Belichick. Whatever the issues between the twin pillars of the organization, they've yet to cost the team on the field.

One need only look to New York, Seattle, and now Pittsburgh to see how difficult it is to build something that truly lasts.